Chronic Pain in Primary Care: Overview and Pathophysiology

Module 1Frances Sonstein, MSN, RN, FNP, CNSMary Lou Adams, PhD, RN, FNP-BC, FAANPaula Worley, MSN, RN, FNP-BC Diane Tyler, PhD, RN, FNP-BC, FNP-C, FAANStephanie Key, MSN, RN, CPNP-PCThe University of Texas at Austin School of Nursing

Consultants: Yvonne D’Arcy, MSN, RN and JoEllen Wynne, MSN, RN, FNP-BC, FAANP

Objectives:Relate impact of chronic pain in

primary care settingsIdentify barriers to optimal chronic

pain managementDefine different types of painDescribe pathophysiology of pain

Goal: provide NPs with a concise and easy to understand overview of pain.

Impact on Primary CarePrevalence of chronic painHealth care costsComplexity of careImpact on all dimensions of

health

Prevalence and cost of chronic painCommon chronic pain conditions affect 116 million US adults at a cost of $560-635 billion annually in direct medical costs and lost productivity.

Healthcare costs $261-300 billionLost productivity $297-336 billion

IOM: “Relieving Pain in America: A blueprint for transforming prevention, care ,education and research (2011)

Complexity of Care and Impact on all dimensions of healthMany providers refuse to see

patients with chronic painPatients with inadequately

managed chronic pain suffer unnecessarily◦Have significant loss in overall

functional status and productivity◦High rate of depression◦Strained social relationships◦Poor quality of life.

Principles of Chronic pain ManagementEffective pain management is a moral

imperativeChronic pain can be a disease in itselfValue of comprehensive treatmentNeed or interdisciplinary approachesImportance of preventionWider use of existing knowledgeThe conundrum of opioidsRoles for patients and clinicians working

togetherValue of a public health and community

health approach

BarriersPatient-related barriers

◦Unwillingness to report pain or accept treatment

◦In older adults, the perception that pain is a part of aging

◦Beliefs good patients don’t complain Strong pain medication should be ‘last resort’

◦Stigma of opioid use◦Access and availability to treatment, since

many providers refuse to treat chronic pain patients

BarriersProvider-related barriers

◦Lack of knowledge◦Lack of diagnostic precision◦Difficulty in choosing the right analgesic◦Lack of standardized approach to

treating pain◦Fear of doing harm◦Legal and regulatory issues◦Limited referral resources◦Attitudes, beliefs, expectations

Types of Pain:Pain

◦An unpleasant , sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage

Acute pain◦ Identifiable etiology◦Self-limited, short duration◦Objective autonomic features

Chronic pain◦Persists > 6 months or beyond the normal

healing period◦Vague, poorly articulated characteristics

Nociceptive PainPhysiologic response to noxious

stimuliInitiated by nociceptors

◦ thermal, chemical, mechanicalSomatic pain

◦ Superficial◦ Deep

Visceral pain

Neuropathic Pain Disorder of neuromodulation Etiology

◦Nervous system injury or dysfunction Characteristics

◦Hyperalgesia◦Hyperesthesia ◦Allodynia◦Hyperpathia

Neuropathic PainExamples

◦Phantom limb pain◦Complex regional pain syndrome◦Diabetic neuropathy◦Central pain syndrome◦Trigeminal neuralgia◦Post-herpetic neuralgia

Myofascial PainMuscle and connective tissue painEtiology

◦Hypertonic muscles◦Myofascial trigger points◦Arthralgias◦Fatigue with muscle weakness

Example◦Fibromylagia

Physiology of PainGate Control Theory

◦Afferent nerve fibers transmit impulses to spinal cord and brain

◦Perception◦Descending pathways◦Modulation

Pain Physiology: Multiple ProcessesTransductionTransmissionNeuromodulationDescending modulation systemsSensitizationPain modulation

Transduction Noxious stimuli are converted to

electrical signals on nociceptors◦C-fibers and A- delta fibers◦Do not respond normally to non-noxious

stimuli ◦Do not adapt◦Release of excitatory neurotransmitters

increase sensitization◦Opioid receptors activated by

endogenous or exogenous opioids slow afferent firing.

TransmissionPeriphery spinal cord thalamus

cortex of the brain via afferent nerve fibers.◦C-fibers are non-myelinated and respond

to mechanical, thermal and chemical stimuli

◦A-delta fibers are thinly myelinated which respond to mechanical and thermal stimuli

◦Release of pain neurotransmitters, such as glutamate and substance P, in the spinal cord.

ModulationInhibitory nervous system

response to noxious painful stimuli◦Intermediate neurons◦Descending neural tracts

Respond to exogenous and endogenous opioids

Open calcium channels Release of Endorphins and enkephalins

Descending Modulation SystemsStimulation of Opioid Receptors

in the midbrain ◦Stimulated by serotonin (5HT) and

norepinephrine (NE) cells◦Inhibit transmission of pain stimuli◦Prevent the release of Substance P

and glutamate◦Inhibit the activation of peripheral

nociceptors

SensitizationSensitization

◦Neurohormonal transmitters such as Substance P, calcitonin gene peptide (CGRP) and adenosine triphophate (ATP) create an “inflammatory soup” even further lowering the pain threshold thus further sensitizing

◦Hyperalgesia- pain augmentation

Pain PathwaySee diagram page 488(permission to reproduce not authorized)

McCance,K., Huether, S. et al. (2010). Pathophysiology: The biologic basis for disease in adults and children (6th ed). Mosby: Philadelphia, PA.(permission to reproduce not authorized)

Pain NeurotransmittersInflammatory Excitatory InhibitoryMediatorsTransmitters Transmitters

Bradykinin Glutamate Gama amino butyric acidLeukotrienes -NMDA (GABA)Prostagandins - AMPA Descending pain modulatorsSerotonin Tachykinins Norepinephrine – alpha 2Substance P Neuronkinin A & B receptorsInterleukins Substance P Serotonin receptorsTumor necrosis Calcitonin gene Opioids receptors factor related peptides (mu, delta, kappa)Nitric Oxide Somatostatins EndodorphinsATP Bombesins EnkephalinsNeurokinins Cholecystokinine DynorphinsCalcitonin gene- related peptide

ImplicationsSummary statement

◦Treatment of chronic pain both pharmacologic and non-pharmacologic including Complementary Alternative Medicine are based on understanding of the various processes in the pain pathway

◦The goal is to enhance modulation of the painful sensation.

Basis for assessment and management◦Determining the type of pain, intensity,

etiology will direct effective management

References Arnstein, P and St. Marie, B. (2010) Managing Chronic Pain with Opioids: A call for change. Executive

Summary of a White paper by the Nurse practitioner Healthcare Alliance Foundation. AM J for Nurse Practititoners 14(11/12), 48-51.

 Committee on Advancing Pain Research, Care, and Education; Institute of Medicine. (2011) Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research. National Academies Press. Available at http://www.nap.edu/catalog.php?record_id=13172

D’Arcy, Y. (2008) Pain in the Older Adult. The Nurse Practitioner 33(3), March, 18- 24.  Dipiro, J., Talbert, R., Yee, G., Matzke, G., Wells, B., and Posey, M. (2011) Pharmacotherapy: A

Pathophysiologic Approach, 8th ed. NY: McGraw Hill, 1045-59. Dobschra, S., Corson, K, Flores. J, Tansill, E and Gerrity, M. (2008) Veterans Affairs Primary Care

Clinicians’ Attitudes toward Chronic Pain and Correlates of opioid prescribing rates. Pain Medicine, 9(5), 564-571.

 errell, B, Fine , P and Herr, K. (2010) Strategies for Success: Pharmacologic Management of Persistent Pain in the Older Adult. Supplement to The Clinical Advisor October 2010.

 Jackman, R and Malllett, B. Chronic Nonmalignant Pain in Primary Care. Am Fam Physician: 78(10) Nov 15, 2008, 1155-62.

 Kaasalainen, S, Martin-Misener R., Carter, N., Disenso, A, Donald F.and Baxter, P (2010) The Nurse Practitioner Role in Pain Management in Long term care. Journal of Advanced Nursing 66(3), 542-551

 McCance,K., Huether, S. et al. Pathophysiology: The biologic basis for disease in adults and children, 6TH ED. MOSBY ELSEVIER PHILA 2010,PAGES 481-495,

 Spitz, A, Moore, A., Papaleontiou, M., Granieri, E., Turner, B. and Reid, M.C. (2011) Primary care providers’ perspective on prescribing opioids to older adults with non-cancer pain: a qualitative study. BMC Geriatrics, 11 (35).

 Tarzian,A. and Hoffmann, D. (2004) Barriers to Managing Pain in the Nursing Home: Findings From a Statewide Survey. J Am Med Dir Assoc 5: 82–88.

Weidemer, N. Harden,P. Arndt, I. and Gallaghere, R. (2007) The Opioid Renewal Clinic: a primary care, managed approach to opioid therapy in chronic pain patients at risk of substance abuse. Pain medicine 8(7), 573-84.

 Vanderah, T.  (2007): Pathophysiology of pain.  Medical Clinics of North America 91, (1) 1-12. WB Saunders.

 Vijayaraghavan, et al.  (2012) Primary Care Providers Views on Chronic Pain Management among High-Risk Patients in Safety Net Settings.  Pain Medicine: 13:1141-48.

Post-Test Questions1. According to the 2011 Institute of Medicine report, “Relieving

Chronic Pain in America”, chronic pain healthcare costs and lost productivity ranges annually:

a. 200-300 million dollars

b. 560-635 million dollars

c. 200-300 billion dollars

d. 560-635 billion dollars

 

2. One of the factors leading to inadequate treatment of chronic pain is:

 

a. Many healthcare providers refuse to see patients with chronic pain.

b. Lack of reimbursement for chronic pain conditions.

c. Lack of adequate treatment regimens.

d. None of the above

Post-Test Questions3. Patient related barriers include unwillingness to report pain and accept treatment, the stigma of opioid use, and decreased access and availability of treatment.  a. True b. False 4. Chronic pain can be described as:  a. pain with vague or poorly articulated characteristics b. pain persisting greater than 6 months c. pain lasting longer than the normal healing time for a specific condition d. all of the above 5. Deep somatic pain in ligaments, bones, joints, muscles and blood vessels is described as which type of pain?  a. Nociceptive b. Neuropathic c. Myofascial

Post-Test Questions6. A normally non-painful stimulus, such as light touch on sunburned skin, causing perception and sensation of pain is:

 

a. Hyperpathia

b. Hyperalgeaia

c. Allodynia

d. Hyperestheaia

 

7. Phantom limb pain, complex regional pain syndrome, diabetic neuropathy, central pain syndrome, trigeminal neuralgia and post-herpetic neuralgia are all examples of :

 

a. Acute nociceptive pain

b. Chronic nociceptive pain

c. Acute neuropathic pain

d. Chronic neuropathic pain

 

Post-Test Questions 8. The process of pain pathway described by Melizak in 1965 involving transmission, perception, descending pathways and modulation is called:  a. Specificity Theory b. Gate Control Theory  9. The stage in the pain pathway in which C-fibers and A- delta fibers conduct the electrical impulses of the perception of pain from the periphery to the spinal cord, the thalamus, and eventually the cortex of the brain releasing pain excitatory neurotransmitters such as glutamate and Substance P is:  a. Transduction b. Transmission c. Modulation d. Sensitization

Post-Test Questions10. Which of the following statements apply to the effective management of chronic pain?

 

a. Requires the clinician determining the etiology, type, intensity of pain.

b. May involve pharmacologic, non-pharmacologic and complimentary alternative medical intervention.

c. Is directed at enhancing the modulation of painful sensation.

d. All of the above.